I see what you mean. It's actually okay to do that, because

just means intensity under one set of conditions (depends on

), while

means intensity under another set of conditions (depends on

).

Oh, you can actually do it this way (might be easier to understand):

Substitute in:

and

Now, using that equation, substitute

, and solve for

This is exactly the same as what I was doing before, except I was doing it in algebra so it may have been confusing, especially with all the subscripts (like

) and superscripts (like

).

You were confusing me with your "^2", it should be "_2" to signify the subscript.

**Superscript:** (notation: x^2)

**Subscript:** (notation: x_2)